The present invention relates to a chip mounter and a method for recognizing a Ball Grid Array (BGA) package in a chip mounter. Various embodiments of the invention relate to an apparatus and method for automatically recognizing and registering information about a BGA package in which solder balls have a plurality of patterns through a chip mounter.
A chip mounter is an apparatus for mounting electronic parts supplied through a part supply apparatus on a printed circuit board (PCB) substrate. Thousands of kinds of electronic parts including an electronic part which includes a BGA package are mounted on a PCB substrate by a chip mounter.
FIG. 1A is a plan view of a typical chip mounter. A chip mounter 1 includes a bed 2, a part supply unit 3 which is mounted on the bed 2 to supply an electronic part 7, a substrate transfer unit 4 which transfers a PCB substrate 5 externally supplied to a part mounting area A, a head 6 which picks up the electronic part 7 supplied by the part supply unit 3 and mounts it on the PCB substrate 5, and a central control unit (not shown) which controls overall operation of the chip mounter 1.
Operation of the chip mounter will be described below with reference to FIG. 1A.
The electronic part 7 supplied by the part supply unit 3 is adhered to and lifted up to a predetermined height using the head 6. Then, the electronic part 7 is transferred to a predetermined location by a transfer unit (not shown). At this time, the electronic part is inspected for defects using, for example, a camera installed in the head 6. The chip mounter 1 mounts the corresponding electronic part 7 at a predetermined location of the PCB substrate 6 if it is determined as not being defective and discards the corresponding electronic part if it is determined as defective.
When inspecting whether an electronic part is defective or not, a method for comparing information of an electronic part which is previously stored and image information of a part obtained using a camera is commonly used in a chip mounter. Therefore, a process for storing information of a corresponding part in advance is required. An auto teaching technique is one of techniques used to this end. That is, a chip mounter includes a part recognition unit which automatically recognizes and stores information of an electronic part supplied from a part supply unit. In order to inspect whether an electronic part is defective or not, a chip mounter compares information of an electronic part which is previously stored and image information of a part acquired by, for example, a camera, and determines an electronic part as normal if the information is identical and as defective if it is not identical.
However, when an electronic part includes a BGA package, particularly when there are two or more patterns of solder balls, there is no technique which automatically recognizes and stores information of an electronic part. Thus, for an electronic part with two or more patterns of solder balls, information of a part is stored such that an expert manually inputs information about some of the solder balls such as a pattern of a solder ball. However, in this case, it takes a long time to store information about a part, and even when an electronic part is inspected for defects by using information of a part manually stored, many errors occur. For example, a normal part can be determined as defective.